tensorflow: tf_upgrade_v2 fails if the file contains f-strings and gives pasta.base.annotate.AnnotationError

System information

• Have I written custom code (as opposed to using a stock example script provided in TensorFlow): yes
• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): macOS 10.14.3
• Mobile device (e.g. iPhone 8, Pixel 2, Samsung Galaxy) if the issue happens on mobile device: NA
• TensorFlow installed from (source or binary): pip install tensorflow==2.0.0-alpha0
• TensorFlow version (use command below): 2.0.0-alpha0
• Python version: 3.6.8
• Bazel version (if compiling from source):
• GCC/Compiler version (if compiling from source):
• CUDA/cuDNN version: NA
• GPU model and memory: NA

Describe the current behavior tf_upgrade_v2 fails if the file contains f-strings

Describe the expected behavior tf_upgrade_v2 does not fails if the file contains f-strings

Code to reproduce the issue File foo.py:

print(f'tf_upgrade_v2 fails to convert f-strings, like this one: {42}')

Command that produces the error: tf_upgrade_v2 --infile foo.py --outfile foo_tf20.py

Other info / logs

Traceback (most recent call last):
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 47, in wrapped
    f(self, node, *args, **kwargs)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1213, in visit_Num
    self.attr(node, 'content', contentargs, deps=('n',), default=str(node.n))
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1352, in attr
    attr_parts.append(attr_val())
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1210, in <lambda>
    contentargs = [lambda: self.tokens.next_of_type(token_number_type).src]
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/token_generator.py", line 347, in next_of_type
    self.lines[token.start[0] - 1]))
ValueError: Expected 'NUMBER' but found ')'
line 1: print(f'tf_upgrade_v2 fails to convert f-strings, like this one: {42}')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/anaconda3/envs/tf2.0/bin/tf_upgrade_v2", line 10, in <module>
    sys.exit(main())
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/tensorflow/tools/compatibility/tf_upgrade_v2_main.py", line 110, in main
    args.input_file, output_file, upgrade)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/tensorflow/tools/compatibility/tf_upgrade_v2_main.py", line 33, in process_file
    upgrader.process_file(in_filename, out_filename)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/tensorflow/tools/compatibility/ast_edits.py", line 494, in process_file
    temp_file)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/tensorflow/tools/compatibility/ast_edits.py", line 548, in process_opened_file
    self.update_string_pasta("".join(lines), in_filename))
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/tensorflow/tools/compatibility/ast_edits.py", line 510, in update_string_pasta
    t = pasta.parse(text)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/__init__.py", line 25, in parse
    annotator.visit(t)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 47, in wrapped
    f(self, node, *args, **kwargs)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 211, in visit_Module
    self.generic_visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 261, in generic_visit
    self.visit(item)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 47, in wrapped
    f(self, node, *args, **kwargs)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 574, in visit_Expr
    self.visit(node.value)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 47, in wrapped
    f(self, node, *args, **kwargs)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 703, in visit_Call
    any_args = self.visit_Call_arguments35(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 770, in visit_Call_arguments35
    self.visit(arg)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 261, in generic_visit
    self.visit(item)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1161, in visit
    super(AstAnnotator, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 127, in visit
    super(BaseVisitor, self).visit(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 253, in visit
    return visitor(node)
  File "/anaconda3/envs/tf2.0/lib/python3.6/ast.py", line 263, in generic_visit
    self.visit(value)
  File "/anaconda3/envs/tf2.0/lib/python3.6/site-packages/pasta/base/annotate.py", line 1163, in visit
    raise AnnotationError(e)
pasta.base.annotate.AnnotationError: Expected 'NUMBER' but found ')'
line 1: print(f'tf_upgrade_v2 fails to convert f-strings, like this one: {42}')